diff --git a/main.c b/main.c
index 24c1346..f473537 100644
--- a/main.c
+++ b/main.c
@@ -46,14 +46,23 @@ int server(int connfd, VB *sim) {
             return 0;
         } else if (read_result == read_result_pending) {
             if (running) {
-                /*
                 cycles = MAX_STEP_CYCLES;
                 brk = vbEmulate(sim, &cycles);
-                */
-                cycles = 0;
-                brk = 0;
                 if (brk) {
                     /* We hit a breakpoint */ 
+                    if (brk == -1) {
+                        /* actually, not implemented */
+                        running = false;
+                        rdb_response_begin_packet(&res);
+                        rdb_response_write_str(&res, "T05:thread:p1.t1;threads:p1.t1;");
+                        result = rdb_response_send_packet(&res);
+                        if (result != 0) {
+                            return result;
+                        }
+                    } else {
+                        fprintf(stderr, "surprising response %d from vbEmulate\n", brk);
+                        return -1;
+                    }
                 } else {
                     sleep_nanos((MAX_STEP_CYCLES - cycles) * 50);
                 }
@@ -137,9 +146,11 @@ int main(int argc, char** argv) {
         return 1;
     }
     /* relevant state at the start of the physics sim's main */
+    /*
     vbSetProgramCounter(sim, 0x070002ba);
     vbSetProgramRegister(sim, 3, 0x0500ffc0);
     vbSetProgramRegister(sim, 4, 0x05008000);
+    */
 
     if (argc > 2) {
         char *end;